The present invention relates to devices for the selective application of fluid operating pressure to groups of brake members associated with the wheels of a vehicle.
More precisely, the invention concerns a device which enables the locking of one or more wheels of the vehicle, with the resulting loss of grip thereof, to be avoided during braking of the vehicle.
Various devices or systems of this type are known in the art.
A first solution currently adopted, particularly in very expensive motor cars, provides for the use of an electric pump as the source of fluid braking pressure. This pressure is then applied to various brake members of the vehicle through respective solenoid valves. This solution allows very good functional results to be obtained but has the disadvantage of being very expensive.
Even higher manufacturing and assembly costs are involved in systems in which the anti-locking function for the wheels is combined with a servobrake system.
Hydromechanical or pneumo-hydraulic anti-locking systems have also been developed which are much cheaper than the solutions described above. The advantages resulting from this cheapness, however, are tempered by difficulties of installation in vehicles, by the dimensions of the system, and (particularly in the case of pneumo-hydraulic systems) by a certain slowness of operation and limitation of the overall brake capacity.